Technical field
[0001]
The present invention relates to a door inner panel and the door inner panel manufacturing method for an automobile.
The present application, to March 23, 2016, claiming priority based on Japanese Patent Application No. 2016-059198, filed in Japan, the contents of which are incorporated here.
BACKGROUND
[0002]
　Car door is produced mainly combining the door inner panel and a door outer panel. The automobile door, window, window driving device, an acoustic speaker, a handle or the like is attached. For housing them, space is required between the door inner panel and a door outer panel. Therefore, for example, the vertical wall portion is provided in the door inner panel. Further, when the vehicle door is closed, it is necessary to seal the interior by a door. Therefore, for example, stepped portion is provided on the vertical wall portion of the door inner panel. By the step portion of the vertical wall portion opposes the vehicle body pillar and the like, car sealing is ensured.
[0003]
　Door inner panels used in automotive side door, etc., is formed by pressing a metal plate such as a steel plate. In general, since the shape of the door inner panel is complex and may be considerably deformed metal plate. In this case, cracking molded door inner panel, you may wrinkle or the like occurs. Therefore, the door inner panel material highly processed metal plate is used. For high workability metal plate has low strength, the strength of the door inner panel is low. Therefore, it is often the door inner panel belt line reinforcement or a door impact beam, etc. is attached as a reinforcing member.
[0004]
　Structure of the door inner panel, disclosed in Patent Documents 1-3.
[0005]
　Door inner panel disclosed in Patent Document 1 includes a beltline reinforcement.
　Beltline reinforcement is joined along a longitudinal direction of the vehicle body at the beltline of the door inner panel. Thus, the belt line reinforcement to bear the impact load in the vehicle longitudinal direction, the bending moment acting can be effectively reduced in the belt line portion, and is described in Patent Document 1.
[0006]
　The door inner panel disclosed in Patent Document 2, when a collision load from the vehicle body side loaded, a door inner panel and the belt line reinforcement is in contact, a load absorption portion of the door inner panel is deformed. Thus, the load absorbing portion for absorbing a portion of the load applied in the thickness direction of the door inner panel, the stiffness of the door inner panel is secured, and are described in the patent document 2.
[0007]
　The side door disclosed in Patent Document 3, the rear end and the front end portion of the belt line reinforcement which is formed by hot stamping is a low strength and low rigidity than the main body portion. Thus, when a collision load from the front of the vehicle body loaded, the rear end portion of the beltline reinforcement is plastically deformed, the contact area between the center pillar increases. Therefore, deformation of the rear end portion of the beltline reinforcement can absorb the energy of the collision, and is described in Patent Document 3.
CITATION
Patent Document
[0008]
Patent Document 1: Japanese Patent 2007-296953 JP
Patent Document 2: Japanese Patent 2008-94353 JP
Patent Document 3: Japanese Patent 2013-112133 JP
Summary of the Invention
Problems that the Invention is to Solve
[0009]
　However, Patent Document 1, the door inner panel Patent Document 2, and Patent Document 3, it is essential separate reinforcing member such as a belt line reinforcement to ensure a collision characteristics. Therefore, the door produced from the door inner panel of Patent Document 1, 2 and 3, the production efficiency is low, the cost is high.
[0010]
　The present invention has been made in view of the above circumstances, and its object is lightweight, excellent door inner panel to the collision characteristics, and to provide excellent door inner panel manufacturing method in productivity.
Means for Solving the Problems
[0011]
　Overview of the present invention is as follows.
[0012]
(1) the first aspect of the present invention, there is provided a door inner panel made of a metal plate, a first panel section having a first vertical wall portion connected to the first top plate portion and the first top plate portion, second top plate portion which is disposed at the first top plate portion and the gap of the first panel section, and a second panel section having a second vertical wall portion leading to the second top plate portion, the comprising a flange portion connected to the first vertical wall portion and the second longitudinal wall portion, and a flat portion disposed between said first panel portion and the second panel section, the first vertical wall portion and the second vertical wall portion each having a stepped portion, both ends of said plate is a door inner panel integral with said flange portion or the stepped portion.
[0013]
(2) the door inner panel according to (1) has an opening in at least one of the first top plate portion and the second top plate portion may be formed.
(3) In the door inner panel according to the above (1), said plate may have the wall portion leading to said first vertical wall portion and the second longitudinal wall portion.
(4) In the door inner panel according to the above (1) may further include a stiffening component which connects said first longitudinal wall portion and the second longitudinal wall portion.
(5) In the door inner panel according to the above (1), at least one of concave and convex portions on said plate may be formed.
[0014]
(6) In the door inner panel according to the above (1), the tensile strength may be more 1200 MPa.
The door inner panel according to (7) above (6), C content, in mass%, it may be 0.11% to 0.35%.
(8) In the door inner panel according to the above (7), the maximum thickness portion T1 in the first top panel section MAX (mm), the minimum thickness portion T1 in the first top plate portion MIN (mm), the maximum thickness portion T2 of the second top plate portion MAX (mm), and the minimum thickness portion T2 in the second top plate portion MIN (mm) is also satisfied the following equation (a) and the formula (b) good. (T1
MAX -T1 MIN ) × 100 / T1 MAX <15 · · · (A) formula (T2 MAX -T2 MIN ) × 100 / T2 MAX <15 · · · (B) formula
[0015]
(9) In the door inner panel according to the above (1), the tensile strength may be 340 ~ 980 MPa.
The door inner panel according to (10) above (9), C content, in mass%, may be 0.001% to 0.150%.
(11) In the door inner panel according to the above (10), the maximum thickness portion T1 in the first top panel section MAX (mm), the minimum thickness portion T1 in the first top plate portion MIN (mm), the maximum thickness portion T2 of the second top plate portion MAX (mm), and the minimum thickness portion T2 in the second top plate portion MIN (mm) is also satisfied the following equation (c) and the equation (d) good. (T1
MAX -T1 MIN ) × 100 / T1 MAX <20 · · · (c) formula (T2 MAX -T2 MIN ) × 100 / T2 MAX <20 · · · (d) formula
[0016]
(12) In the door inner panel according to the above (1), the height of the second vertical wall portion and said first vertical wall portion may be respectively 40mm or more.
The door inner panel according to (13) above (1), the said plate, the width of the minimum width portion is not less 30mm or more, the width of the maximum width portion may be not more than 200 mm.
[0017]
(14) A second aspect of the present invention, the above (1) to a method for producing a door inner panel according to any one of (13), made of the metal plate, the first plate portion a preparation step of preparing a blank having a third flat plate portion positioned between the second flat plate portion and the second flat plate portion and the first flat plate portion, and the die, an inner punch facing the die , an outer punch facing the die is disposed outside of the inner punch and the blank holder, the pressing device comprising, on the first flat plate portion and the second flat plate portion of the blank, cold or hot between, subjected to press working, the blank and a pressing step of forming the door inner panel, in the pressing step, the inner punch, said one of the first flat plate portion of said blank door inner path Processing the area to be formed into the second top plate portion of the door inner panel of the second flat plate portion region and the blank to be formed into the first top plate portion Le, the outer punch, the region is formed into the stepped portion of the door inner panel of the second flat plate portion of the area and the blank is formed into the stepped portion of the door inner panel of the first flat plate portion of said blank processed, the processing of the blank by the outer punch is completed earlier than the processing of the blank by the inner punch.
[0018]
The door inner panel manufacturing method according to (15) above (14), the press working step, the inner punch and the outer punch can be further processed to a portion of the third flat plate portion of said blank .
In the manufacturing method of the door inner panel according to (16) above (14), the press working step, before the pushing of the blank by the outer punch is completed, push the blank by the inner punch begun it may be.
(17) In the manufacturing method of the door inner panel according to the above (14), when performing the press working step between said heat heating temperature may be not more than Ac3 point.
Effect of the invention
[0019]
　The door inner panel according to the above (1), since the first vertical wall portion and the second vertical wall portion has a stepped portion, in addition to improving the sealing of the vehicle, it is possible to increase the rigidity of the door inner panel .
　Furthermore, both ends of the flat portion disposed between the first panel portion and the second panel portion is connected integrally with the flange portion or the stepped portion. Flat plate portion which is integrated in the door inner panel to serve as a door impact beam, there is no need to provide a separate door impact beam. Further, according to this structure, when the door inner panel is combined with a door outer panel, the flat plate portion is disposed at a position closer to the door outer panel. Thus, the collision energy applied from the door outer panel side can be efficiently absorbed by the flat plate portion.
　Thus, while reducing the weight of the door inner panel, it is possible to exhibit excellent crashworthiness.
[0020]
　The door inner panel according to the above (2), by which the opening is formed in the first top panel section or the second top plate portion, it is possible to weight reduction.
　Further, in the first top panel section or the second top plate portion, it is possible to process by flanging extends in the vicinity of the opening, and the first vertical wall portion or the second vertical wall portion of the height (flange portion as a reference press it is possible to increase the forming depth). This makes it possible to increase the rigidity of the door inner panel. Further, when the door inner panel is combined with a door outer panel or the like, since the flat plate portion can disposed further close to the door outer panel, it is possible to further improve the crashworthiness.
[0021]
　Has been at the door inner panel according to the above (3), by having a wall plate portion is connected to the first vertical wall portion and the second vertical wall portion, the cross section of the flat plate portion is a U-shaped, flat plate portion second moment is increased. Thereby, the collision energy is absorbed by the flat plate portion is increased, it becomes possible to further improve the crashworthiness.
　The door inner panel described in the above (4), by a first vertical wall portion and the second vertical wall portion which are spaced from each other across the flat plate portion is connected by stiffening components, the rigidity of the door inner panel it is possible to increase. Therefore, it is possible to further improve the crashworthiness.
　The door inner panel described in the above (5), by concave or convex portions are formed on the flat portion, the second moment of the flat plate portion is increased. Thereby, the collision energy is absorbed by the flat plate portion is increased, it becomes possible to further improve the crashworthiness.
[0022]
　In been door inner panel production method according to (14), it can be formed by a single pressing the above-mentioned door inner panel.
　However, to say that one of the pressing process, there is a case where the cutting process and the piercing step after the pressing process.
　Further, after the machining of the blank by the outer punch is completed, completing the machining of the blank by the inner punch. Accordingly, in a state where the step portion is constrained by an outer punch and a die, so that the molding of the first top plate portion and the second top plate portion by the inner punch is completed. Therefore, in any of the step of pressing the cold and hot, it is possible to suppress occurrence of molding defects such as cracks and wrinkles in the door inner panel.
　Therefore, the above-described door inner panel efficiently, and the molding failure can be produced by suppressing.
[0023]
　In been door inner panel production method according to (15), it is possible to plate portion is formed by a single pressing a door inner panel having a wall portion.
　However, to say that one of the pressing process, there is a case where the cutting process and the piercing step after the pressing process.
　Further, in has been the door inner panel production method according to (16), before the step part by the outer punch and die is restrained, because the inner punch is pushes the blank somewhat, thickness of the top plate portion it is possible to suppress the reduction of. Therefore, it is possible to more reliably suppress occurrence of molding defects such as cracks and wrinkles in the door inner panel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024]
It is a perspective view of a door inner panel viewed from a vehicle inner side according to the first embodiment of FIG. 1A] present invention.
[FIG 1B] is a perspective view of the door inner panel from the vehicle outer side according to the embodiment.
[FIG 2A] is a schematic view of a cross section perpendicular to the vertical direction of the vehicle body of a typical automotive side door.
[FIG 2B] is a schematic view of a cross section perpendicular to the vertical direction of the vehicle body of the side door of the door inner panel is applied according to the embodiment.
3 is a perspective view of the door inner panel viewed from a vehicle inner side of the first modified example.
4 is a perspective view showing a part of a door inner panel according to the second modification.
[FIG 5A] is a perspective view of the door inner panel viewed from a vehicle inner side of the third modification.
[FIG. 5B] is a perspective view seen from the vehicle outer side of the door inner panel according to the third modification.
[FIG 6A] is a sectional view schematically showing an example of a press apparatus used in the door inner panel manufacturing method according to a second embodiment of the present invention.
It is an A-A arrow view of FIG. 6B] FIG 6A.
7 is a plan view of the blank used in the door inner panel manufacturing method according to the above embodiment.
8 is a plan view of the blank in the case of producing a door inner panel according to the third modification.
In FIG 9A] stamping is a sectional view showing a step of sandwiching the blank in the blank holder.
In FIG. 9B] stamping is a sectional view showing a state where pushing by outside punch is completed.
In FIG 9C] stamping is a sectional view showing a state where the push by the inner punch is completed.
In FIG 10A] stamping is a sectional view showing a step of sandwiching the blank in the blank holder.
In FIG 10B] stamping is a sectional view showing a state where the push is completed by outside punch after pushing by the inner punch has started.
In FIG 10C] stamping is a sectional view showing a state where the push by the inner punch is completed.
11 is a sectional view showing a state during pressing by common pressing device.
It is a perspective view showing a panel - door inner when the convex shape was given to [12] the flat plate portion.
13 is a perspective view showing a door inner panel of a comparative example.
Is a plan view for explaining a calculation method of FIG. 14A] gravimetric efficiency K.
It is a side view for explaining the calculation method of FIG. 14B] gravimetric efficiency K.
DESCRIPTION OF THE INVENTION
[0025]
　Hereinafter, the present invention will be described in detail based on the first embodiment and the second embodiment with reference to the drawings. In the figure, the description thereof is not repeated the same reference numerals designate like or corresponding parts.
[0026]
(First Embodiment)
　Hereinafter, description will be given door inner panel 1 according to a first embodiment of the present invention with reference to FIGS. 1A and 1B.
　Door inner panel 1 according to the present embodiment is obtained by press molding using a steel plate S as a blank. 1A is a door inner panel 1 of the embodiment is a perspective view from the vehicle inner side, FIG. 1B is a perspective view of the door inner panel 1 of the embodiment from the vehicle outside.
　As shown in FIGS. 1A and 1B, the door inner panel 1 includes a first panel portion 10, a second panel portion 20, a flat plate portion 30 and a flange portion 40. In the following description, there are cases where the direction perpendicular to the plane of the flange portion 40 is referred to as the pressing direction.
[0027]
　The first panel portion 10 has a first top plate portion 11 which is formed from the flange portion 40 at a position spaced in the pressing direction, and a first vertical wall portion 12 leading to the edge of the first top plate portion 11 .
[0028]
　The first vertical wall portion 12 is provided so as to face the vehicle body pillar and the like, a part to increase the vehicle sealability.
　The first vertical wall portion 12 includes a top plate side first vertical wall portion 12a extending along the pressing direction is bent from the vehicle front and rear sides of the first top plate portion 11, the flange portion 40 the first step portion 12c for connecting the flange portion side first vertical wall portion 12b extending along the pressing direction by bending, and a top plate portion side first vertical wall portion 12a and the flange portion side first vertical wall portion 12b including the door. The first step portion 12c is between the flange portion 40 and the first top plate portion 11, substantially to the plane of the flange portion 40 is parallel to.
[0029]
　The second panel portion 20, are formed spaced apart from the first panel portion 10 via the flat plate portion 30 in plan view.
　The second panel section 20 has a second top plate portion 21 which is formed from the flange portion 40 at a position spaced in the pressing direction, and a second vertical wall portion 22 leading to the edge of the second top plate portion 21 .
[0030]
　The second vertical wall portion 22, like the first vertical wall portion 12 is provided so as to face the vehicle body pillar and the like, a part to increase the vehicle sealability.
　The second vertical wall portion 22, and four outer edges 21a, 21b, 21c, the second vertical wall portion 22a top plate portion extending along the pressing direction is bent from 21d of the second top plate portion 21 , connecting the flange portion side second vertical wall portion 22b extending along the pressing direction is bent from the flange portion 40, and a second vertical wall portion 22a and the flange portion side second vertical wall portion 22b top wall side and a second step portion 22c. Second stepped portion 22c is between the flange portion 40 and the second top plate portion 21, substantially to the plane of the flange portion 40 is parallel to.
　Since the top plate portion side second vertical wall portion 22a of the second top plate portion 21, the four outer edges 21a adjacent to each other, 21b, 21c, are continuously formed along the 21d, the door inner panel it is possible to increase the first stiffness.
[0031]
　The first top plate portion 11 has a square planar shape, the second top plate portion 21 has a pentagonal shape in plan view. The vehicle upper side of the first top plate portion 11 forms the belt line BL.
[0032]
　The second top plate portion 21, four outer edges 21a of the second top plate portion 21, 21b, 21c, the openings 50 so as to leave a peripheral portion adjacent to 21d are formed. A position corresponding to the opening 50, the acoustic speaker or a handle or the like is attached.
　If the opening 50 to the second top plate portion 21 as the door inner panel 1 according to this embodiment is formed, becomes easier to stretch flangeability due to the opening 50 is widened during pressing. Therefore, not only the weight reduction can be achieved by weight reduction, occurrence of molding defects such as wrinkles and cracks can be suppressed.
[0033]
　Flange portion 40, around the first panel portion 10 and the second panel portion 20 is formed so as to be connected to the second flange portion side one vertical wall portion 12b and the flange portion side second vertical wall portion 22b.
[0034]
　The flat plate portion 30 is a section responsible for the door impact beam, is formed in a strip shape so as to distinguish between the first panel portion 10 in the plan view and the second panel portion 20. The flat plate portion 30 to be formed in a band shape (straight), the shape of the mold is simple, it is possible to suppress the manufacturing cost.
　The flat plate portion 30 is integrally formed with the flange portion 40. Therefore, since the door inner panel need not attach a separate door impact beams, it is possible to reduce the weight of the door inner panel. The end portion of the flat plate portion 30 are preferably formed in the flange portion 40 and flush.
[0035]
　As shown in FIG. 1B that, if the width of the flat portion 30 W1, the width of the door inner panel 1 and W, the ratio W1 / W of W1 and W is 0.05 or more and 0.6 or less It is preferred.
　When the ratio W1 / W is too small, the bending strength of the flat plate portion 30 is low, the flat plate portion 30 can not be sufficiently absorb the collision energy. Thus, a preferred lower limit of the ratio W1 / W is 0.05.
　When the ratio W1 / W is too large, the area of the first panel portion 10 and the second panel portion 20 is small, it is difficult to ensure the rigidity of the door inner panel 1. The area of the flat plate portion 30 becomes too large, it is difficult to install items such as a speaker. Accordingly, the preferred upper limit of the ratio W1 / W is 0.6.
　For example, of the flat plate portion 30, the minimum width portion is of width 30mm or more, the width of the widest portion is preferably less 200 mm.
[0036]
　The flat plate portion 30 is preferably provided in a region corresponding to the vehicle door lock striker. Figure 1A, as shown in FIG. 1B, in the area where the flat plate portion 30 is provided, there is a gap between the first vertical wall portion 12 and the second vertical wall portion 22. This is because that can accommodate the hook or the like for the door lock to this gap.
[0037]
　Since both ends of the flat plate portion 30 in the door inner panel 1 according to the present embodiment is connected to the flange portion 40, and the door inner panel 1 is combine a door outer panel or the like, at a position flat portion 30 comes close to the door outer panel It will be provided. Thus, it is possible to improve the crashworthiness of the door. It will be described in detail below this point.
[0038]
　Figure 2A is a schematic diagram of a cross section perpendicular to the vertical direction of the vehicle body of a typical automotive side door.
　Side door is produced by combining the door outer panel A and the door inner panel 1000. Space SP is a space between the door outer panel A and the door inner panel 1000. The space SP, acoustic speakers, window, window driving device and the like are housed. When an automobile is a side collision, the load P to the door outer panel A (white arrow in FIG. 2A) is loaded. With a door outer panel A is deformed by the load P, the vertical wall portion 1001 of the door inner panel 1000 is deformed. The vertical wall portion 1001 of the door inner panel 1000 to absorb the impact energy by the load P. That is, in order to improve the crashworthiness of the side door, it is necessary to improve the strength of the door inner panel. However, the material of the conventional door inner panel 1000 is low strength mild steel plate. The shape of the door inner panel as described above is complicated, because the processing is difficult. Mild steel plate, for example, tensile strength of the steel sheet of about 270 MPa. Therefore, the side door of a conventional automobile, it is essential to reinforced by separate reinforcing member such as a door impact beam D shown in Figure 2A.
[0039]
　For side door provided with a reinforcing member such as a door impact beam D, when the door outer panel A by the load P is deformed in the vehicle interior, the door outer panel A hits the door impact beam D. Thus, collision energy is absorbed in the door impact beam D not only the door inner panel 1000, the collision characteristics of the side door is improved.
　However, since it is necessary to attach the door impact beam D is another component to the door inner panel 1000, a conventional assembled door heavier, absorbed energy (absorption energy gravimetric efficiency) per unit weight is low. Moreover, since it is necessary to install another component, the manufacturing cost of the conventional door is high, production efficiency is low.
[0040]
　Figure 2B is a schematic diagram of a cross section perpendicular to the vertical direction of the vehicle body of the side door of the door inner panel 1 according to this embodiment is applied. Side door includes a door inner panel 1, and a door outer panel A, a. Door outer panel A is arranged on the vehicle outer side of the door inner panel 1, it is joined to the door inner panel 1.
　In the side door, the door inner panel 1 according to this embodiment, the flat plate portion 30 is disposed at a position close to the door outer panel A. Therefore, when the door outer panel A is deformed in the vehicle interior by the collision, the door outer panel A hits the flat plate portion 30. Therefore, the collision energy, among the respective portions of the door inner panel 1, because it is first absorbed in the flat plate portion 30, the collision characteristics of the side door is improved.
　Thus, the flat plate portion 30 of the door inner panel 1 according to this embodiment, in order to function as a replacement for door impact beams, side door the door inner panel 1 is applied according to the present embodiment, the door impact beam even without, excellent collision properties.
[0041]
　Next, a description of the material for the door inner panel 1 of the embodiment.
　Door inner panel 1 according to the present embodiment is obtained by press molding using a steel plate S as a blank, the characteristics of the steel sheet S as the case of performing the case and cold press molding to perform hot press-forming be selected Te is preferred.
[0042]
　When press-molding the door inner panel 1 by hot press forming, subjected to press molding in a state where the tensile strength was heated steel sheet S of 500 MPa ~ 1000 MPa or more Ac3 point, by then performing the quenching, over 1200MPa it is preferable to use a steel sheet S having components such as tensile strength are obtained.
[0043]
　In particular, the carbon content of the steel sheet S (C content) is preferably not more than 0.35% 0.11% or more by mass%.
　If C content is 0.11% or more, it can exhibit good hardenability, which is preferable easily and more 1200MPa tensile strength of the door inner panel 1. C content is more preferably 0.15% or more.
　On the other hand, if the C content is 0.35% or less, preferably it is possible to suppress the poor welding. C content is more preferably 0.30% or less.
　Si, Mn, P, S, Al, for the components of B, etc., may be suitably adjusted.
[0044]
　If the door inner panel 1 according to this embodiment is press-molded using a steel sheet S of a high strength of at least 440 MPa, measures in particular the first top plate portion 11, as wrinkles and cracks in the second top plate portion 21 does not occur it is necessary to carry out.
　The first top plate portion 11, the second top plate portion 21, portions that locally sheet thickness reduction occurs, it will cause generation of cracks, in order to enhance the crashworthiness first top plate portion 11, a it is preferable that the thickness at Deva plate portion 21 is uniform.
[0045]
　Thus, when employing a hot press forming, the maximum thickness portion of the first top plate portion 11 T1 MAX (mm), the minimum thickness portion of the first top plate portion 11 T1 MIN was (mm) case, it is preferable to the following equation (1) is satisfied. (T1
MAX -T1 MIN ) × 100 / T1 MAX <15 · · · (1) formula
[0046]
　Similarly, the maximum thickness portion of the second top plate portion 21 T2 MAX (mm), the minimum thickness portion of the second top plate portion 21 T2 MIN is case of a (mm), satisfy the following expression (2) it is preferable. (T2
MAX -T2 MIN ) × 100 / T2 MAX <15 · · · (2) the formula
[0047]
　When press-molding the door inner panel 1 by cold press forming, it is preferable to use a steel sheet having a tensile strength of 340 MPa ~ 980 MPa.
[0048]
　In particular, the carbon content of the steel sheet S (C content) is preferably not more than 0.001% to 0.150% in mass%.
　If C content is 0.001% or more, which is preferable the tensile strength of the door inner panel 1 easily and more 340 MPa. C content is more preferably 0.08% or more.
　On the other hand, if the C content is less 0.150%, preferably possible to exhibit good press formability. C content is more preferably 0.12% or less.
　Si, Mn, P, S, Al, for the components of B, etc., may be suitably adjusted.
[0049]
　As in the case of press-molding the door inner panel 1 by hot press forming, even when the door inner panel 1 is press-molded by cold pressing, in particular the first top plate portion 11, wrinkles in the second top plate portion 21 and cracking it is necessary to take measures so as not to generate. The first top plate portion 11, places the local thickness reduction is in the second top panel section 21, it will cause generation of cracks, in order to enhance the crashworthiness first top plate portion 11, a it is preferable that the thickness at Deva plate portion 21 is uniform.
[0050]
　Therefore, when adopting the cold press forming, the maximum thickness portion of the first top plate portion 11 T1 MAX (mm), the minimum thickness portion of the first top plate portion 11 T1 MIN was (mm) case, it is preferable that the following formula (3) is satisfied. (T1
MAX -T1 MIN ) × 100 / T1 MAX <20 · · · (3) the formula
[0051]
　Similarly, the maximum thickness portion of the second top plate portion 21 T2 MAX (mm), the minimum thickness portion of the second top plate portion 21 T2 MIN is case of a (mm), satisfy the following equation (4) is it is preferable. (T2
MAX -T2 MIN ) × 100 / T2 MAX <20 · · · (4) formula
[0052]
　Incidentally, hot press forming, even when adopting either of cold press forming, the first top plate portion 11, in order to make the thickness uniform in the second top plate portion 21 will be described later door like the inner panel manufacturing method, preferred to employ a manufacturing method to complete the first step portion 12c, the first top plate portion 11 after completing the processing of the second step portion 22c, the machining of the second top plate portion 21 it is.
[0053]
　Hereinafter, FIGS. 3, 4, 5A, and, with reference to FIG. 5B illustrating the various modifications of the door inner panel 1 according to the embodiment.
[0054]
(First Modification)
　FIG. 3 is a perspective view of the door inner panel 1A according to the first modification of the vehicle interior.
　In the door inner panel 1A, is different from the door inner panel 1 according to the first embodiment in that both ends of the flat plate portion 30 are connected first stepped portion 12c, the second stepped portion 22c.
　That is, in the door inner panel 1A, both ends of the flat plate portion 30, a first step portion 12c, is provided so as to integrate into the second stepped portion 22c.
[0055]
　The first panel portion 10, leading flange 40 and the step portion (the first step portion 12c, the second stepped portion 22c) through a second panel portion 20. Accordingly, the door inner panel 1A, as compared with the door inner panel 1 according to the first embodiment, a large area where the first panel portion 10 is connected to the second panel portion 20. Therefore, the door inner panel 1A is stiffer than the door inner panel 1 according to the above-described embodiment.
[0056]
　However, the flat plate portion 30 of the door inner panel 1A, as compared with the flat plate portion 30 of the door inner panel 1 according to the embodiment, is disposed from the door outer panel at a position far. Therefore, from the viewpoint of the impact properties of the door, it is preferable for the door inner panel 1 according to the above-described embodiment. In short, the arrangement of the flat plate portion 30, the collision properties of the door, is appropriately set in consideration of the rigidity of the door inner panel.
[0057]
　Figure 3 h1 shown in shows the flange portion 40 stepped portion (first step portion 12c, the second stepped portion 22c) of the pressing direction of the height up.
　h2 shows the flange portion 40 the top plate (first top plate portion 11, the second top plate portion 21) of the pressing direction of the height up.
　Door inner panel 1A according to this modification, h2 ≧ 40 mm and, preferably satisfies the condition h1 / h2 <0.8. In the case of h2 <40mm, it is because space SP to accommodate the window or the like is too small. For h1 / h2 ≧ 0.8, the stepped portion (first step portion 12c, the second stepped portion 22c) and the top plate (first top plate portion 11, the second top plate portion 21) the distance between the close , car sealability is lowered.
[0058]
(Second Modification)
　FIG. 4 is a perspective view showing a door inner panel 1B according to the second modification. In the door inner panel 1B, to increase the rigidity, stiffening component 60 is provided for connecting the first panel portion 10 and a second panel portion 20.
　As shown in FIG. 4, stiffening component 60 is a member which connects the first stepped portion 12c and the second stepped portion 22c of the first vertical wall portion 12 and the second vertical wall portion 22. Thus, since the first panel section 10 connected to the second panel portion 20, increasing the overall rigidity of the door inner panel 1B is. Stiffening component 60 is, for example, a steel plate is press-processed plate-shaped parts. Stiffening parts 60 may be, for example, it is bonded to the first panel portion 10 to the second panel section 20 by welding.
[0059]
(Third Modification)
　Fig. 5A, 5B show a door inner panel 1C according to a third modification.
　5A is a perspective view of the door inner panel 1C from the vehicle inner side, FIG. 5B is a perspective view of the door inner panel 1C from the vehicle outside.
　Door inner panel 1C according to the third modification, the flat plate portion 30 is different from the door inner panel 1 according to the embodiment in that a wall portion 31. Other configurations of the door inner panel 1C according to this modification is the same as the door inner panel 1 according to the embodiment.
　In the door inner panel 1C, since the flat plate portion 30 has a wall portion 31, the cross-sectional shape of the flat plate portion 30 is a U-shape. Therefore, compared with the flat plate portion 30 of the door inner panel 1 according to the embodiment is a flat shape, geometrical moment of inertia of the flat plate portion 30 is enhanced. That is, the collision energy flat plate portion 30 having a wall portion 31 is absorbed, greater than the crash energy flat plate portion 30 of the door inner panel 1 according to the embodiment absorbs. Further, the wall portion 31 leads to a first vertical wall portion 12 and the second vertical wall portion 22. Therefore, it is possible to enhance the overall rigidity of the door inner panel 1C.
[0060]
(Second Embodiment)
　Hereinafter, a door inner panel manufacturing method according to a second embodiment of the present invention will be described with reference to FIGS. 6A ~ 11.
　Door inner panel manufacturing method according to the present embodiment is for press-molding the door inner panel 1 according to the first embodiment, the step of preparing a steel plate S as a blank (the blank preparation step), the press apparatus and a step (pressing step) pressing a steel sheet S between cold or hot by.
[0061]
　6A, 6B is a sectional view schematically showing a press apparatus 100 used in the step of pressing the door inner panel manufacturing method according to this embodiment.
　Figure 6A, of the press apparatus 100 is a sectional view showing a portion corresponding to the first panel portion 10 of the door inner panel 1, FIG. 6B is an A-A arrow view of FIG. 6A.
　Figure 6A, 6B, the pressing device 100 includes an inner punch 101 and an outer punch 102, the blank holder 103, and a die 104. In the press apparatus 100, in a state of being fixed by sandwiching the steel sheet S by the blank holder 103 and the die 104, by pushing the inner punch 101 and an outer punch 102 into the recess of the die 104, inner door shown the steel sheet S in FIG. 1 it can be formed into a shape of the panel 1.
[0062]
　Inner punch 101, and a second inner punch 101b having a first inner punch 101a having a shape corresponding to the first top plate portion 11, a shape corresponding to the second top plate portion 21.
　As shown in FIG. 6B, the inner punch 101 of the press apparatus 100, there is a form and the first inner punch 101a and the second inner punch 101b is divided across the portions corresponding to the flat plate portion. By using such inner punch 101, it is shallower than the press-molding the depth of a portion corresponding to the press forming depth of the portion corresponding to the flat plate portion 30 to a first top plate portion 11 and the second top plate portion 21 it is possible.
　However, a first inner punch 101a and the second inner punch 101b completely eliminate the need to be divided, only the portion corresponding to the flat plate portion 30 is a single inner punch 101 formed in a groove shape it may be.
[0063]
　The outer punch 102 is disposed outside the inner punch 101, a first outer punch 102a having a shape corresponding to the first stepped portion 12c, and a second outer punch 102b having a shape corresponding to the second stepped portion 22c a.
　As shown in FIG. 6B, in the press apparatus 100, by which the first outer punch 102a and the second outer punch 102b is a shed form across the portions corresponding to the flat plate portion 30, the flat plate portion 30 it is possible to shallower than the press-molding the depth of a portion corresponding to the press forming depth of the portion corresponding to the first stepped portion 12c and the second stepped portion 22c to.
　However, a first outer punch 102a and the second outer punch 102b completely eliminate the need to be divided, only the portion corresponding to the flat plate portion 30 is a single inner punch 101 formed in a groove shape it may be.
[0064]
　In the case where the door inner panel 1A according to the first modification will be press-molded, it is preferable to use the outer punch first outer punch 102a and the second outer punch 102b is not divided.
[0065]
　Blank holder 103 is in the outside of the outer punch 102 is arranged so as to face the die 104 and the press axis. By sandwiching the blank holder 103 and the die 104, it is possible to fix the steel sheet S at the time of press molding.
　The blank holder 103, the shape of the flange portion 40 of the door inner panel 1 is formed.
[0066]
　Die 104, the inner punch 101, with respect to the outer punch 102 and the blank holder 103, is arranged opposite to the press direction, the recess of the shape corresponding to the door inner panel 1 is formed.
[0067]
　When pressing a steel sheet S between heat, the steel plate S in the heated state was press-molded in a mold, are preferably formed by hot stamping to perform as it cooled in the mold. Thus, the press apparatus 100 may comprise a heating device and cooling device.
　Incidentally, when performing hot stamping, in order to obtain a suitable quenching effect, it is preferable to press-forming the steel sheet S that has been heated above Ac3 point.
[0068]
　Next, steps of preparing a steel sheet S (the blank preparation step).
　Characteristics of preparations for the steel sheet S is as described in the first embodiment described above, it is preferable to selectively use in the cases of hot pressing and cold pressing.
[0069]
　Figure 7 is a plan view of the steel sheet S in the case of producing FIG. 1A, the door inner panel 1 shown in FIG. 1B. Steel S has a first flat plate portion S1, the second flat plate portion S2, the third flat portion S3, and the opening S4.
　The first flat plate portion S1 is a portion corresponding to the first panel portion 10. The second flat plate portion S2 is a portion corresponding to the second panel portion 20. The third flat portion S3 is a portion corresponding to the flat plate portion 30. Opening S4 is a portion corresponding to the opening 50.
　Region depicted by hatching in FIG. 7 is a region facing the inner punch 101. Region drawn by the intersection hatching in FIG. 7 is a region facing the outer punch 102.
[0070]
　As shown in FIG. 7, the opening S4 is between the first flat plate portion S1 and the third flat plate portion S3, and, provided between the second flat plate portion S2 and the third flat plate portion S3. As described above, when the steel sheet S has an opening S4, stretch flange easily molded. However, even if the steel sheet S without an opening S4, if it can mold the steel sheet S, the openings S4 are unnecessary.
　However even in this case, it is preferable to have a cut which divides the steel sheet S to the first flat plate portion S1, the second flat plate portion S2 and the third flat plate portion S3,.
　Steel having such a shape is obtained by stamping a steel plate.
　For cold forming, if ductility and stretch flangeability has the material of about 340 ~ 980 MPa, FIG. 1A, it is possible to form a door inner panel 1 shown in FIG. 1B.
[0071]
　Incidentally, FIG. 5A, when the door inner panel 1C according to a third modification shown in FIG. 5B is press-molded, since the flat plate portion 30 has a wall portion 31, it is preferable to use a steel sheet S shown in FIG.
　In the steel sheet S shown in FIG. 8, processing a portion of the third flat plate portion S3 of the inner punch 101 and the outer punch 102 further steel plate S. Thus, the wall portion 31 of the flat plate portion 30 is molded.
　Region depicted by hatching in FIG. 8 is a region facing the inner punch 101. Region drawn by the intersection hatching in FIG. 8 is a region facing the outer punch 102.
[0072]
　The following describes stamping.
　In the press working process, the pressing device 100 described above, the first flat plate portion S1 and the second flat plate portion S2 of the steel sheet S, between cold or hot, subjected to press working. Thus, shaping the steel sheet S to the door inner panel 1. More specifically, the inner punch 101, a region to be molded to the first top plate portion 11 of the first flat plate portion S1 of the steel sheet S, the second top plate portion 21 of the second flat plate portion S2 of the steel sheet S the region to be molded and processed, the outer punch 102, a region to be molded in the first step portion 12c of the first flat plate portion S1 of the steel sheet S, the second stepped portion 22c of the second flat plate portion S2 of the steel sheet S processing the area to be shaped into.
[0073]
　When performing the press working step in hot, it is preferable to perform hot stamp at the same time pressing a steel sheet S that has been heated above Ac3 point, quenching the molded door inner panel.
　When carrying out the stamping operation in hot steel sheet S is heated prior to pressing. Steel sheet S is heated by an unillustrated heater. Steel S is only to be heated above A1 point of the material is preferably heated above the Ac3 point to obtain a more reliable quenching effect.
　If the steel sheet S is heated above point A1, the metal structure of the door inner panel after quenching intensity becomes martensite becomes high.
　The heating temperature is, for example, 700 ~ 900 ° C.. The heating temperature is, the material is appropriately set by the molding difficulty level. In hot stamping, for heating to soften the steel sheet S, it is possible to mold complex shapes.
[0074]
　In the press working process, the processing of the steel sheet S by the outer punch 102, to be completed before the processing of the steel sheet S by the inner punch 101. Thus, cracks molded door inner panel, the molding defects such as wrinkles can be prevented from being generated.
[0075]
　Figure 9A ~ 9C are cross-sectional view of the pressing process is shown schematically in the door inner panel manufacturing method according to the present embodiment.
　9A shows a step of stifle placed steel sheet S to the die 104 with the blank holder 103 (the initial stage).
　Figure 9B shows a state where pushing by the outer punch 102 is completed (intermediate stage).
　Figure 9C shows a state where pushing by the inner punch 101 is completed (final stage).
[0076]
　In the initial stage shown in FIG. 9A, the steel sheet S is placed on the die 104. In this state, the slide of the press device (not shown) is lowered. Thus, sandwiching the steel sheet S between the blank holder 103 and the die 104.
　If pressing between hot, in the initial stage shown in FIG. 9A, the interval between the blank holder 103 and the die 104 is greater than the thickness of the steel sheet S is preferred. That is, a gap is provided between the steel sheet S and the blank holder 103. The size of the gap is, for example, 0.1 mm. When contacted with the steel sheet S to the blank holder 103, before the steel sheet S is press-formed, the portion which contacts the blank holder 103 of the steel sheet S is cooled. Therefore, since the cooling rate of the steel sheet S is partially different, the strength of the molded article differs depending on portions. Therefore, it is preferable that a slight gap is provided between the blank holder 103 and the steel sheet S.
[0077]
　In the intermediate stage shown in FIG. 9B, completed pushing by the outer punch 102, the steel sheet S is in a state of being draw-formed by the outer punch 102 and die 104. In this case, the inner punch 101 is the same height as the outer punch 102.
　The door inner panel manufacturing method according to the present embodiment, simultaneously with the pushing of the steel sheet S by the outer punch 102 is completed, and starts pushing the steel sheet S by the inner punch 101.
[0078]
　In the final stage shown in FIG. 9C, a state in which indentation has been completed the steel sheet S by the inner punch 101 is started from the state shown in FIG. 9B.
[0079]
　The door inner panel manufacturing method according to the above embodiment, when the pressing of the steel sheet S by the outer punch 102 is completed, the position of the height of the inner punch 101 is the same height as the outer punch 102. However, the position of the height of the inner punch 101 at this time may be in a position lower than the outer punch 102.
　That is, as shown in FIGS. 10A ~ FIG 10C, before the pressing of the steel sheet S by the outer punch 102 is completed, may be begun pushing the steel sheet S by the inner punch 101.
　Further, when the pressing of the steel sheet S by the outer punch 102 is completed, the position of the height of the inner punch 101 may be in a position lower than the outer punch 102. That is, after the pressing of the steel sheet S by the outer punch 102 is completed, may be begun pushing the steel sheet S by the inner punch 101.
　In any case, the push by the inner punch 101 is not completed before the pushing by the outer punch 102. Incidentally, Osaekomi of the steel sheet S by the blank holder 103 and the die 104 may be made done until the molding of the outer punch is completed.
　Figure 9A ~ Figure 9C, although FIGS. 10A ~ FIG. 10C illustrates the case where there is no opening in the steel plate S, if there is an opening in the steel plate S in the subsequent completion of the pushing by the outer punch 102, the inner punch 101 material is moved vertical wall from the top plate during molding, to stretch flange deformation, it is possible to suppress more cracking.
[0080]
　According to the door inner panel manufacturing method according to the present embodiment, complete pressing of the steel sheet S by the outer punch 102, then, is completed pressing of the steel sheet S by the inner punch 101. Therefore, when the pushing by the outer punch 102 is then the steel sheet S is squeezed by molding completed, pressed portion by the outer punch 102 of the steel sheet S is constrained by an outer punch 102. Thus, it is possible to suppress wrinkles or the like generated in the vicinity of the step portion of the door inner panel. It will be described in detail below this point.
[0081]
　Figure 11 is a sectional view showing a state during pressing by common pressing device 200. In Figure 11, an enlarged view of a portion of the die 220 of a typical press apparatus 200. In the press apparatus 200, the punch 210 is not divided into inner and outer. Therefore, when lowering the punch 210, a portion V1 of the steel sheet V is not constrained by the punch 210 and die 220. That is, a portion V1 of the steel sheet V is not in contact with the punch 210 and die 220.
　If pressing cold, in the stage shown in FIG. 11 in the press working, part V1 of the steel sheet V is not constrained by the punch 210 and die 220. Therefore, a portion V1 of the steel sheet V is easily bent, prone to wrinkles.
[0082]
　On the other hand, if the pressing by the hot steel plate and the punch, to cool the steel sheet by contact with the die or the like. Therefore, in the stage shown in FIG. 11 in the press working, part V1 of the steel sheet V is not cooled. Portion V1 of the steel sheet V is the punch 210 when further pushed from the position shown in FIG. 11, is cooled. In short, if the shape of the top plate portion and the step portion of the door inner panel is formed by the punch 210 which is shaped integrally with the door inner panel step portion is provided on the vertical wall portion, a portion V1 of the steel sheet V another It is cooled later than the parts.
[0083]
　If the cooling of the steel sheet V is partially delayed, the strength of the steel sheet V and ductility partially different. In this case, cracks in the door inner panel to be molded, wrinkles are likely to occur.
　Figure 1A, as shown in FIG. 1B, if the first vertical wall portion 12 and the second vertical wall portion 22 of the door inner panel 1 has stepped portions 12c, the 22c, in particular cracks, wrinkles are likely to occur. If the strength of the door inner panel after the molding is high, further cracks, wrinkles are likely to occur.
[0084]
　Door inner panel manufacturing method of this embodiment, as shown in FIGS. 9A ~ Figure 9C, using a pressing device 100 having an inner punch 101 and an outer punch 102. Thus, FIG. 1A, the first top plate portion 11 (or the second top plate portion 21) and the first stepped portion 12c of the door inner panel 1 as shown in FIG. 1B (or the second stepped portion 22c) are independently It is molded by the punch.
　In addition, pushing by the outer punch 102 is completed earlier than the pushing by the inner punch 101. Thus, when one of the punch forming the top plate, the other punch stifle stepped portion of the door inner panel 1. Accordingly, when molding the top plate, it can be constrained are not portions of the steel sheet S is reduced, suppressing the wrinkles of the door inner panel 1 and the like.
[0085]
　It has been described an embodiment of the present invention. However, the above-described embodiment is merely an example for implementing the present invention. Accordingly, the present invention is not limited to the embodiments described above, it can be implemented by changing the embodiment described above without departing from the scope and spirit thereof as appropriate.
[0086]
　For example, in the above description has described a door inner panel for a motor vehicle side door. However, a door inner panel of the present embodiment is not limited to a side door. Door inner panel of this embodiment is also applicable to other side door, such as the rear door. Further, the door inner panel of the present embodiment is not limited to automotive. Door inner panel is applicable to products requiring excellent crashworthiness. Such products are, for example, vehicles, construction machinery, an aircraft or the like.
[0087]
　In the above embodiment has been described when the material of the door inner panel is steel. However, the material of the door inner panel is not limited to steel, it may be a metal plate. Metal plates such as aluminum plate, aluminum alloy plate, multilayered steel, titanium plate, a magnesium plate. In addition, the steel sheet may be used as a tailored blank. Tailored blank is tailored welded blanks (hereinafter, also referred to as "TWB") and, tailored rolled blanks (hereinafter, also referred to as "TRB") are classified into. TWB is thickness, tensile strength, etc. welding is different kinds of steel sheets: is obtained by integrating the (Example butt welding). Meanwhile, TRB by changing the distance between the rolling rolls when producing the steel sheet, in which varying thickness. With tailored blanks, it is possible to enhance the strength by only where required, it is also possible to reduce the plate thickness. In addition, the door inner panel using the tailored blanks can also be applied to an automobile. Thus, it is possible to improve the crashworthiness, further views of the lighter.
[0088]
　In the above-described embodiment, the flat plate portion 30 is formed into a flat strip (straight), the flat plate portion 30 may be formed to be curved in plan view, even if the concave portions or convex portions are formed good. As an example, FIG. 12 illustrates a 'door inner panel 1 having a' recessed flat portion 30 formed. In this case, increasing the second moment of the flat plate portion 30, it is possible to improve the strength of the door inner panel 1. Further, it may be formed with both a concave and convex portion.
[0089]
　In the above-described embodiment, the flat plate portion 30 extend in parallel to the belt line BL in the plan view, the flat plate portion 30 may not extend parallel to the belt line BL. That is, the flat plate portion 30 may be at an angle to the belt line BL.
　In the embodiment described above, the four outer edges 21a of the second top plate portion 21, 21b, 21c, but the second vertical wall portion 22 which extends bending is provided from 21d, the second vertical wall portion 22 need only extend bent from each side of the two or more adjacent sides of the outer edge of the second top plate portion 21.
　In the above embodiment, the planar shape of the first top plate portion 11 is a square, planar shape of the second top plate portion 21 is pentagonal. However, the planar shape of the first top plate portion 11 and the second top panel section 21 only needs to be designed appropriately according to the shape of the vehicle.
[0090]
　In the above-described embodiment, the opening 50 is provided only one position of the second top plate portion 21, the number of openings 50 is not limited to one location, to the second top plate portion 21 a plurality of openings 50 may be formed. The opening 50 may be formed in the first top plate portion 11. Shape of the opening 50 is circular, elliptical, it may be polygonal or the like, not particularly limited. Further, the second top plate 21 may not be openings 50 are formed. Even without opening 50 and when the second top plate portion 21 can be formed, if a speaker or the like is not required, the openings 50 are not necessary.
[0091]
　In the above-described embodiment, the first vertical wall portion 12 and the second vertical wall portion 22 shows a case extending perpendicular to the first top plate portion 11 and the second top panel section 21, not strictly perpendicular it may be.
　In the above-described embodiment shows a case where the surface of the first stepped portion 12c and the second stepped portion 22c is parallel to the first top plate portion 11 and the second top panel section 21, not exactly parallel it may be.
[0092]
　In the above embodiment, showing a case where the second vertical wall portion 22 that four adjacent outer second longitudinal wall portion 22 has a stepped portion (first step portion 12c and the second stepped portion 22c). That is, there the second vertical wall portion 22 adjacent the three sets, but shows the case where the three pairs both with a step portion (first step portion 12c and the second stepped portion 22c), the number of sets is not limited to three pairs .
　In the above-described embodiment shows a case where the step portion is one step, or may be a plurality of stages.
[0093]
(Example)
　As a blank was prepared steel sheet A ~ F shown in Table 1. The HS after TS in Table 1, was press-molded while heating the steel above Ac3 point, means a tensile strength in the case of cooling in the mold.
[0094]
[Table 1]

[0095]
　To the steel plate A ~ F, FIG. 6A, using a pressing device having a shape shown in FIG. 6B, went FIG. 1A, the press forming of a door inner panel of the shape shown in Figure 1B.
　As a comparative example, a conventional door inner panel C. shown in FIG. 13 assembled with the reinforcing member of the material of the inner door of the same kind by spot welding Press molding was carried out of the E.
　Thus it performs collision four-point bending test for each of the resulting door inner panel to determine the weight efficiency K of the absorption energy of the impactor displacement 100mm (J / g). Gravimetric efficiency K is as follows.
[0096]
　First, as shown in FIG. 14A, and the three points of the door inner panel by bolts. Then, by impinging the impactor R127mm as shown in FIG. 14B, to determine the absorption energy of the impactor displacement 100 mm (J). Then, a value obtained by dividing the weight of the door inner panel comprising a reinforcing portion or reinforcing member and the weight efficiency.
[0097]
　Further, in Table 2, shows the weight efficiency K1 in the case of the reinforcing member together, when the weight efficiency K2 in the case of the reinforcing member by with weight efficiency ratio calculated by 100 × K1 / K2 (percent) It was.
[0098]
[Table 2]

[0099]
　As shown in Table 2 above, according to the present invention example, compared to the case of attaching separate reinforcing members, it became possible to increase the absorbed energy per unit weight while maintaining the working efficiency is shown It was.
Industrial Applicability
[0100]
　According to the present invention, light collision characteristics and productivity superior door inner panel, and can provide a manufacturing method thereof.
DESCRIPTION OF SYMBOLS
[0101]
1, 1A, 1B, 1C door inner panel
10 first panel section
11 first top plate portion
12 first vertical wall portion
12a top plate side first vertical wall portion
12b flange portion side first vertical wall portion
12c first step part
20 the second panel portion
21 and the second top plate portion
21a, 21b, 21c, 21d outer edge
22 second vertical wall portion
22a top plate side second vertical wall portion
22b flange portion side second vertical wall portion
22c second stepped portion
30 the flat plate portion
31 the wall portion
40 the flange portion
50 opening
60 stiffening parts
door A outer panel
BL beltline
D door impact beam
S steel (blank
material) 100 pressing device
101 inside the punch
102 outside punch
103 blank holder
104 die
S1 of the first flat plate portion
S2 of the second flat plate portion
S3 of the third flat plate portion
S4 opening

The scope of the claims
[Requested item 1]
A door inner panel made of a metal plate,
a first panel section having a first vertical wall portion connected to the first top plate portion and the first top plate portion,
　the first top plate portion of the first panel portion second top plate portion arranged with a gap between, and a second panel section having a second vertical wall portion leading to the second top plate portion,
　the first vertical wall portion and the second vertical wall portion a flange portion connected to,
　a flat plate portion disposed between said first panel portion and the second panel portion
comprises a,
　each of the first vertical wall portion and the second vertical wall portion is stepped portion It has,
　at both ends of the flat plate portion is integrated with the flange portion or the stepped portion
, characterized in that, the door inner panel.
[Requested item 2]
　Openings are formed in at least one of the first top plate portion and the second top plate portion
, characterized in that, the door inner panel of claim 1.
[Requested item 3]
　It said plate has a wall portion leading to said first vertical wall portion and the second vertical wall portion
, characterized in that, the door inner panel of claim 1.
[Requested item 4]
　Further comprising a stiffening part that connects the said second longitudinal wall portion and the first vertical wall portion
, characterized in that, the door inner panel of claim 1.
[Requested item 5]
　At least one of the concave and convex portions are formed on said plate
, characterized in that, the door inner panel of claim 1.
[Requested item 6]
　Tensile strength is not less than 1200MPa
, characterized in that, the door inner panel of claim 1.
[Requested item 7]
　C content, in mass%, 0.11% to 0.35%
, characterized in that, the door inner panel of claim 6.
[Requested item 8]
　Maximum thickness portion T1 in the first top panel section MAX (mm), the minimum thickness portion T1 in the first top plate portion MIN (mm), the maximum thickness portion T2 in the second top panel section MAX (mm) , and the minimum thickness portion T2 of the second top plate portion MIN (mm) is, satisfies the following formula (1) and (2)
, characterized in that, the door inner panel of claim 7. (T1
MAX -T1 MIN ) × 100 / T1 MAX <15 · · · (1) Equation (T2 MAX -T2 MIN ) × 100 / T2 MAX <15 · · · (2) formula
[Requested item 9]
　Tensile strength is 340 ~ 980 MPa
, characterized in that, the door inner panel of claim 1.
[Requested item 10]
　C content, in mass%, 0.001% to 0.150%
, wherein the door inner panel of claim 9.
[Requested item 11]
　Maximum thickness portion T1 in the first top panel section MAX (mm), the minimum thickness portion T1 in the first top plate portion MIN (mm), the maximum thickness portion T2 in the second top panel section MAX (mm) , and the minimum thickness portion T2 of the second top plate portion MIN (mm) is satisfied the following equation (3) and (4)
, characterized in that, the door inner panel of claim 10. (T1
MAX -T1 MIN ) × 100 / T1 MAX <20 · · · (3) Equation (T2 MAX -T2 MIN ) × 100 / T2 MAX <20 · · · (4) equation
[Requested item 12]
　Height of the second vertical wall portion and said first vertical wall portion is respectively 40mm or more
, characterized in that, the door inner panel of claim 1.
[Requested item 13]
　The said plate,
　the width of the minimum width portion is not less 30mm or more,
　the width of the maximum width portion is equal to or less than 200mm
, characterized in that, the door inner panel of claim 1.
[Requested item 14]
　A method of manufacturing a door inner panel according to any one of claims 1 to 13,
　made of the metal plate, the first flat plate portion, said a second flat plate portion and the first flat plate portion second a preparation step of preparing a blank having a third flat plate portion positioned between the flat plate portion,
　the die and an inner punch facing the die, facing the die is disposed outside of the inner punch by pressing apparatus includes an outer punch and blank holder, and the first flat plate portion and the second flat plate portion of the blank, between cold or hot, subjected to press working, the door inner said blank comprising a pressing step of forming the panel, and
　in the press working step,
　the inner punch region to be formed into the first top plate portion of the door inner panel of the first flat plate portion of said blank Processing the area to be formed into the second top plate portion of the door inner panel of the second flat plate portion of the fine the blank,
　the outer punch, the door of the first flat plate portion of said blank processing the region to be molded into the stepped portion of the door inner panel of the second flat plate portion region and the blank to be formed into the stepped portion of the inner panel,
　the processing of the blank by the outer punch completed earlier than the processing of the blank by the inner punch
door inner panel manufacturing method characterized by.
[Requested item 15]
　The pressing at the processing step, the inner punch and the outer punch further processing a portion of the third flat plate portion of the blank
door inner panel manufacturing method according to claim 14, characterized in that.
[Requested item 16]
　Wherein in the pressing step, before the pushing of the blank by the outer punch is completed, push the blank by the inner punch begins
door inner panel manufacturing method according to claim 14, characterized in that.
[Requested item 17]
　When performing the press working step between said heat, the heating temperature is above Ac3 point
door inner panel manufacturing method according to claim 14, characterized in that.